Building bridges of hope: Reconnecting wildlife and ecosystems safely
The Trans-Canada Highway wildlife crossing near Canmore, Alberta, in the Bow Valley.
Photo credit: NM Lister, 2025
Climate change, biodiversity loss and habitat fragmentation have severed critical ecological corridors with highways and urban sprawl. Each year, these disruptions affect animal movement, migration and survival. Additionally, wildlife-vehicle collisions have resulted in human deaths, injuries and damages.
Transforming how we share space with wildlife
To restore ecosystems and reconnect fragmented habitats, Nina-Marie Lister, a professor at the School of Urban and Regional Planning at Toronto Metropolitan University (TMU), studies and advises on the planning and design of a network of wildlife crossings from Alberta to Los Angeles. From overpasses to tunnels, these projects provide safe wildlife passages across North America’s busy roadways, supporting breeding, feeding, gene flow, migration and overall ecosystem resilience. They’re also highly effective at preventing collisions between animals and vehicles.
“These projects are building bridges of hope and opportunity,” said professor Lister. “They show us what’s possible when we take infrastructure seriously as a tool for coexistence.”
Trailblazing in Canada: Setting the standard for wildlife crossings
Professor Lister’s team and partner ARC Solutions pioneered a network of crossings in Canada’s Rocky Mountains. Overpasses in Banff (1996) and Yoho National Parks (2018) spanning the Trans-Canada Highway have become global models.
Over time, these wildlife passages have proven remarkably successful, with over 90% reduction in vehicle-wildlife collisions when located correctly and designed for the appropriate target species. Cameras routinely capture images of grizzly bears, black bears, lynx, cougars, wolves, elk and a diversity of smaller mammals using the crossings regularly. “These crossings are the prototype for all of North America,” said professor Lister. “We know they work.”
The next step was to take these crossings beyond park boundaries, where wildlife still needs safe passage. “The early crossings in Banff National Park showed us what’s possible,” professor Lister said. “Now it’s important that we are expanding the network – designated wildlife corridors with a system of wildlife crossing structures that protect where animals live and move every day – not just inside parks.”
The opening of the Bow Valley Crossing near Canmore, Alberta, in 2023, was the first of its kind spanning the Trans-Canada Highway outside a Canadian national park. Built on the traditional territory of the Stoney Nakoda people and followed by another under construction on Highway 3 in British Columbia, these crossings offer an integrated set of solutions for future development.
“We’re providing an integrated system: a resilient toolbox for how we might mitigate and adapt as migratory patterns shift,” professor Lister said.
Collaborating on California’s landmark crossing
The latest project is the Wallis Annenberg Wildlife Crossing outside Los Angeles. Set to open in early 2026, it will be the world’s largest wildlife overpass, spanning 10 lanes of U.S. Route 101, one of the busiest highways in North America.
Noise and light pollution from the approximately 300,000 vehicles that pass daily will be absorbed by the newly installed bridge decking and soundproof walls, creating a safe and welcoming environment for wildlife. The recently added deep drainage layer, topped with a custom-designed organic soil layer ranging from one to four feet, will support the growth of native vegetation sourced from genetically adapted local seed stock, enhancing and supporting the habitat.
Already, cameras have recorded a curious owl as the “first crossing.” While the project was motivated by the death of beloved mountain lion P-22 (also known as the “lonely bachelor of Hollywood Hills”) in a vehicle collision, it will serve a wide array of species, from bobcats to butterflies. “This is truly a bridge for biodiversity,” professor Lister emphasized. “It’s a large living landscape that serves to reconnect many and diverse species in a region fragmented by roads.”
The Wallis Annenberg Wildlife Crossing in Los Angeles, California, after the decking and before the soil layer is added.
Photo credit: NM Lister, 2024
Strengthening connections: Building a continental conservation network
Through federal government and foundation support, professor Lister’s work has expanded to include partners like the Yellowstone to Yukon Conservation Initiative, a transboundary, transcountry conservation effort aimed at connecting and protecting a vast, ecologically significant region in North America. These partnerships extend the reach of crossing infrastructure across a continental conservation network.
Professor Lister is speaking at the first-ever Canadian Ecological Connectivity Conference in Banff, Alberta this month. She is talking about how to better design an integrated system of crossings for biodiversity recovery and resilient landscapes, and fostering partnerships across Canada.
This research was supported by the Social Sciences and Humanities Research Council.
Learn more about ARC Solutions. (external link)
Related links:
